Pressure relief valve with pressure indicating means

• US 4,232,698 A
• Filed: 09/28/1978
• Issued: 11/11/1980
• Est. Priority Date: 09/28/1978
• Status: Expired due to Term

• Current Assignee: Hosterman Craig
• Original Assignee: Advanced Technology Products Incorporated
• Inventors: Kerwin, William J., Hosterman, Craig
• Primary Examiner(s): Schwadron, Martin P.
• Assistant Examiner(s): Gerard, Richard
• Application Number:
  US05/946,627
• Time in Patent Office: 775 Days
• Field of Search: 73/718, 73/724, 73/714, 361/283, 220/89 A, 137/68 R, 137/557
• US Class Current: 137/68.18
• CPC Class Codes: F16K 17/16 with fracturing diaphragm ; Rupture discs
• CPC Class Codes: F16K 37/0041 for measuring valve parameters F16K37/0033 takes precedence
• CPC Class Codes: F17C 13/025 having the pressure as the parameter
• CPC Class Codes: F17C 2205/0332 Safety valves or pressure relief valves
• CPC Class Codes: F17C 2205/0394 in direct contact with the pressure vessel
• CPC Class Codes: F17C 2221/011 Oxygen
• CPC Class Codes: F17C 2221/016 Noble gases (Ar, Kr, Xe)
• CPC Class Codes: F17C 2223/0123 gaseous, e.g. CNG, GNC
• CPC Class Codes: F17C 2223/035 High pressure (>10 bar)
• CPC Class Codes: F17C 2250/0626 Pressure
• CPC Class Codes: F17C 2260/042 Reducing risk of explosion
• CPC Class Codes: G01L 9/0072 using variations in capacitance
• CPC Class Codes: Y10S 137/91 Destructible or deformable element constructed of specific material
• CPC Class Codes: Y10T 137/1684 With alarm or indicator
• CPC Class Codes: Y10T 137/1729 Dome shape
• CPC Class Codes: Y10T 137/8326 Fluid pressure responsive indicator, recorder or alarm

Abstract

An adjustably positionable element having a curved end plate is located in proximity to the conventional rupturable curved disc in a pressure relief valve for high pressure cylinders. The end plate serves as one plate of a capacitor and the curved disc serves as the other plate. Impedance variation responsive circuitry senses any change in impedance of the capacitor due to a change in flex of the curved disc brought about by a variation in pressure within the cylinder to which the relief valve is attached. The change in impedance is calibrated to provide an indication of the actual pressure within the cylinder.

Claims

1. A pressure relief valve apparatus operatively attached to a high pressure cylinder for providing an indication of the pressure within the cylinder, said apparatus comprising in combination:

a. impedance means disposed within the pressure relief valve for providing an impedance representative of the pressure within the cylinder, said impedance means comprising a capacitor and including a flexible disc flexibly responsive to the pressure within the cylinder, said disc being electrically coupled as a positionable plate of said capacitor, said disc being rupturable in the event of a pressure rise within the cylinder above a predetermined value;

(b) an end plate disposed in proximity to said disc in fixed relationship thereto, said end plate being electrically coupled as a fixed plate of said capacitor; and

(c) means for sensing the impedance and providing an indication reflective of the pressure within the cylinder;

whereby, movement of said disc relative to said end plate varies the impedance of said capacitor.

2. The apparatus as set forth in claim 1 wherein said apparatus includes:

a. an electrical insulator attached to the pressure relief valve;

b. a pedestal for supporting said end plate; and

c. means for maintaining said pedestal fixedly secured to said insulator for electrically insulating said end plate from said disc.

3. The apparatus as set forth in claim 2 wherein the pressure relief valve includes an internally threaded shank and said insulator includes external threads for mating with the internal threads of said shank.

4. The apparatus as set forth in claim 3 including relief ports disposed in proximity to said disc for venting the fluid from the cylinder in the event of rupture of said disc.

5. A pressure relief valve for high pressure cylinders, said pressure relief valve comprising in combination:

a. a disc for flexibly responding to the pressure within the cylinder, said disc being rupturable in the event of a pressure rise within said cylinder above a predetermined value;

b. an end plate disposed in proximity to said disc; and

c. means for supporting said end plate and electrically insulating said end plate from said disc;

whereby, said disc and said end plate are electrically connectable as the plates of a capacitor.

6. The pressure relief valve as set forth in claim 5 wherein said end plate includes a pedestal and said insulating means includes means for securing said pedestal to said pressure relief valve.

7. The pressure relief valve as set forth in claim 6 wherein said pressure relief valve includes:

a. a collar for securing one side of said disc in fluid communication with the contents of the cylinder;

b. a hollow shank extending from said collar; and

c. means for engaging said insulating means with said hollow shank to locate said end plate in proximity to said disc.

8. The pressure relief valve as set forth in claim 7 wherein said insulating means comprises an externally threaded apertured plug for receiving said pedestal and said hollow shank includes internal threads for mating with the external threads of said plug.

9. The pressure relief valve as set forth in claim 8 including means for sensing the impedance of the capacitor developed by said disc and said end plate.

10. The pressure relief valve as set forth in claim 5 including means for sensing the impedance of the capacitor developed by said disc and said end plate.

11. The pressure relief valve as set forth in claim 5 including relief ports disposed in proximity to said disc for venting the fluid from the cylinder in the event of rupture of said disc.